$\"\"$

The equations are $\"\"$ .

Graph each line on a coordinate planes.

$\"graph$

$\"\"$

perpendicular lines: Two nonvertical lines are perpendicular if the product of their slopes is $\"\"$ 1.

Observe the above graph, the line equations $\"\"$ and $\"\"$ are perpendicular.

Parallel lines: Two nonvertical lines are parallel if they have the same slope.

The line equations $\"\"$ are parallel. $\"\"$

The perpendicular lines are $\"\"$ and $\"\"$ .

The parallel lines are $\"\"$ .